Avoton is certainly an improvement on the ridiculously slow and inefficient Centerton, but it is not as efficient as ARM chips. The 40nm Calxeda server node uses 6-7W in total including DRAM and interconnect, while 4C Avoton starts at 13W - that's only for the CPU, not the DRAM and interconnects...

Calxeda will move to 28nm with their next generation in a few weeks and 20nm next year. Then there is AMCC with X-Gene, AMD with Hierofalcon, NVidia with Denver - all having 8 and 16-core 64-bit ARM server chips to be released in 2014 and 2015. It looks like Avoton will end up in the exact same situation as Atom is today.

Any attempt of Calxeda to server market is just now truncated, Avoton is clearly a winner in the perf/watt parameter and this will be good even for 20nm planar Calxeda socs. Not a chance, once Calxeda will shift to A57 the power consumption will grow like a hell.

Moreover there is a 16 core Intel Soc in Q3/2014, bye bye competitors.

The Avoton is a 34 X 28 mm2 package, and the photo seems to indicate the die is about 1/10 (~1/3 X 1/3) of that so I estimate now about 100 mm2 for Avoton, which would be about 4x the years ago die size of Atom Silverthorne. At that time the package was as small as 13 X 14 though it was often 22 X 22.

I seriously doubt Intel can beat ARM on perf/W. AnandTech showed several 6W Calxeda nodes beating low power Xeon CPUs on performance as well as perf/Watt. Next-gen 28nm Calxeda nodes based on A15 will be available in a few weeks, and should improve performance as well as perf/W further.

So Intel can only win by comparing not-yet-released 22nm chips with 40nm ones which have been shipping for a year...

And the real like for like comparison will be next year with 64-bit Cortex-A57 on 20nm. A57 is significantly faster than A15 and reaches far higher frequencies as well.

Actually, performance per watt is probably more important to a degree to the server market than cost. Keep in mind that power is an ongoing expense while you only pay once for the chip - at least until Intel and the other chip companies can figure out a way to lease them...

Also, the CPU chip cost is only one component of the cost for a server, both in terms of dollars and watts. Do we know how different a server board BOM cost is between ARM and x86? Likewise, is the only significant power usage difference between those server boards the CPU itself?

There's no doubt that Intel can beat ARM when using performance per Watt as a metric. However traditionally ARM beats Intel on cost. So in devices where best performance is not the goal (smartphones, tablets e.t.c) ARM won and will continue to win because of its lower cost.

It will be interesting to see who wins on the server front. Performance is obviously more crucial in servers....But the cost metric is also just as important.